Magnets lose their magnetic properties, when

Concept:

Curie Temperature: It is the temperature at which a magnetic material undergoes a sharp change in its magnetic properties.

• Above this temperature, some materials lose their magnetism.
• Above this temperature, ferromagnetic material becomes paramagnetic.

Explanation:

• When a ferromagnetic material is heated to Curie temperature, it disrupts the arrangements of the molecules and a weak magnetic behavior remains.
• This weak magnetic behavior is called Paramagnetic.
• Above this temperature, the paramagnetism property also decreases.
• Upon cooling, it regains its ferromagnetic behavior.
• Hence magnets loose their magnetic properties when heated above curie temperature.​
• Most soft iron bars are temporary magnets.
• They lose their magnetic property when
  1. Hammered
  2. Heated
  3. Dropped to the hard floor with a force.
• Temporary magnets retain their magnetic properties for a short period of time.

Additional Information

Magnetic field: The region around a magnet where its influence is experienced is called the magnetic field.

• The visual representation of the magnetic field is called magnetic field lines.

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​Properties of magnetic field lines:

1. ​​The field lines start from the north pole and end at the south pole.
2. Inside the magnet, the field lines are from the south to the north pole. 
3. The field lines are crowded where the magnetic field is the strongest.
4. The field lines form continuous curves.
5. The field lines do not intersect. If they intersect this will mean there is two directions of the magnetic field at the same time